The present invention relates generally to cushions assembled with a plurality of spring coils and, more particularly, to such a spring cushion assembly suitable for use in a mattress comprised of a combination of spring coils which oppose one another either by opposing inclinational or rotational tendencies, e.g., right-hand and left-hand spring coils.
Spring cushion assemblies of the aforementioned type are well known within the furniture industry for use as so-called innerspring constructions for mattresses as well as other forms of upholstered furniture. Characteristically, such cushion assemblies comprise a plurality of resiliently compressible spring coils arranged in adjacent side-by-side disposition in a selected systematic array, most commonly in linear rows and columns, and connected together, e.g., by metal bands, clips, strings, helical wires, or the like, to form an integrated spring cushion assembly. Such spring cushion assemblies used for mattresses also commonly include border wires, which may be continuous or discontinuous, forming a perimeter outwardly about and connected to the upper and lower end turns of the outermost spring coils.
The types, configurations and constructions of the spring coils utilized in such spring cushion assemblies are quite diverse and may differ, for example, according to the type and size (gauge) of the wire from which the spring coils are made, whether the upper and lower end turns of each spring coil are closed (typically by knotting the terminal wire ends to a medial point along the end coil) or open (i.e., the terminal wire ends are left free and unconnected), the number of intervening coil turns between the opposite end turns (which may be a whole number of turns or may include a one-half coil turn), and whether the spring coils are separate wire units or part of a common length of wire, as with so-called continuous coil spring units (see, e.g., U.S. Pat. Nos. 4,053,956 and 4,358,097).
In producing any given spring cushion assembly, the selection among these various characteristics for the spring coils is made according to considerations of the desired spring characteristics for the cushion assembly (e.g., spring compressibility, strength, etc.), cost, structural stability and rigidity of the cushion assembly, etc. For example, spring coils whose end turns are closed by knotting tend to utilize more wire and to be more expensive to produce than open-ended spring coils. However, open-ended spring coils constructed with a full number of coil turns exhibit a pronounced tendency to incline laterally and to rotate in the direction of their hand (clockwise for right-hand coils and counterclockwise for left-hand coils) when compressed. Hence, when spring cushion assemblies are made of open-ended spring coils, it is not uncommon to utilize spring coils each of a right-hand coiling in each alternating row of spring coils and to utilize spring coils each of a left-hand coiling in each intervening row of spring coils, because the oppositely handed spring coils will tend to incline and rotate in opposite directions under compression and thereby will tend to counter balance one another and enhance the lateral stability of the overall cushion spring assembly.
It is accordingly an object of the present invention to provide further improvements in spring cushion assemblies of the aforementioned type and, in particular, to provide a spring cushion assembly with more enhanced lateral stability against spring coil incline. and rotation than in the prior art.
Briefly summarized, the present invention addresses the foregoing objective by providing a spring cushion assembly which comprises a plurality of spring coils each of which is of a configuration producing a tendency to incline laterally when compressed. According to the present invention, the plurality of spring coils are aligned with one another in parallel linear spring coil rows and parallel linear spring coil columns perpendicular to the spring coil rows, with each spring coil row and each spring coil column having spring coils oriented relative to one another to incline in opposing directions for counteracting the tendency of the spring coils to incline.
Various embodiments of this basic construction are contemplated. For example, in one preferred embodiment, the spring coils comprise right-hand and left-hand spring coils alternating with one another within each row and each column. This embodiment offers the advantage that the oppositely handed spring coils counteract their respective tendencies to rotate oppositely as well as to incline oppositely. Alternatively, however, it is also contemplated that a spring cushion assembly in accordance with the present invention may be formed entirely of spring coils of the same hand by orienting alternating and intervening spring coils within each row and column in opposing orientations, e.g., rotated one hundred eighty degrees from one another, whereby each spring coil tends to incline oppositely to each adjacent spring coil so as to effectively counteract each other. It is further contemplated that the invention could be embodied in a spring cushion assembly made of continuous coil units by forming the alternating and intervening spring coils in each common length of wire to be of opposing orientations or opposing hands.
In many possible embodiments, the spring coils will be of the open-ended type having open upper and lower end turns, and often will have a full number of coil turns therebetween. Many embodiments will also have multiple helical connector wires extending between adjacent spring columns for connecting the respective upper and lower end coils thereof and with upper and lower perimeter border wires disposed outwardly about the spring coils and connected to the upper and lower end turns of the outermost spring coils, thereby for integrating the spring coils together. Preferably, the spring cushion assembly is adapted for use as a mattress spring assembly.